U.S. patent application with Ser. No. 12/338,724 was filed on Dec. 18, 2008. The US Government had certain rights in that invention. That invention disclosed the use of multiwell format or using multiwell plates for analysis of environmental samples. The claimed property in this invention and improvements to the multiwell format was not conducted using US Government funds, and hence there are no US Government rights to this invention.
Environmental and industrial hygiene samples originate from a number of places, such as industrial sites, waste storage and dumps, around these areas in air, water and soil, or those that may have been contaminated by terrorist, military or other acts. Some of the toxic industrial materials are lead, hexavalent chromium, cadmium, mercury and beryllium to name a few prominent ones. These materials are typically analyzed by extracting the toxin or the contaminant in a liquid medium (using acids, bases and other solvents and solutions) and then subjecting this to analysis. Typical analysis involves taking these samples and analyzing them sequentially through chromatography (e.g., high performance liquid or gas chromatography), inductively coupled plasma along with atomic emission or a mass spectrometer (ICP-AES and ICP-MS respectively). The samples are eluted into the equipment in a sequence with enough gaps or purges so that there is no cross-contamination. To decrease the labor content and increase the efficiency of the analysis, autosamplers have been developed for such instruments. In these the samples are put in a queue, and the samples are automatically analyzed one after the other. As an example in modern ICP-MS instruments 200 samples may be queued which may take 10 hours to analyze. This causes many issues related to the drift in baseline, and for proper quantification one may require calibration standards to be run periodically during this long analysis time.
The rapid techniques developed in biological analysis lend themselves to high throughput analysis. In these methods the high throughput is obtained in two ways, first by automating the sample preparation and secondly by developing instrumentation that can analyze a large number of samples within minutes. As an example, microarray and microwell formats are routinely used and are then analyzed by optical scanners (by looking for fluorescence, luminescence and absorption/transmission changes and quantifying these). Typical microwell formats have 24, 96, 384 or 1536 or more wells in an area of about 8 cm×13 cm. Such plates can be read by the optical scanners in a matter of minutes. Microarrays may have thousands of analytical spots on a plate. Further, standards occupy some of the spots or wells so that they are all read almost simultaneously (within minutes) avoiding temporal drift.
In addition to be able to read the samples rapidly, it is highly preferable to automate the sample preparation procedures which require repetitive steps of mixing various liquids, filtration, pipetting, and weighing. The purpose of this invention is to enable high throughput analysis of environmental samples and innovate specific steps so that those steps which are unique for our analysis can be conducted in a seamless fashion. This will reduce cost and enable one to take more samples in order to ensure that safety is not compromised due to the throughput issues.
One object of the present invention is to demonstrate that environmental and industrial hygiene samples can be measured at high throughputs.
Another objective of this invention is to enable processes so that environmental and industrial hygiene samples could be prepared by using automatic pipettes configured to work with optical liquid level sensors.
Yet another objective is to automate the sample preparation and analysis to analyze uranium by phosphorescence.
Another objective of this invention is to produce dye solutions with low inherent optical fluorescence which can be used for beryllium analysis using fluorescence by high throughput or any other methods